This invention relates to a method for mounting pieces inside the vacuum chamber of an electron microscope, particularly a scanning electron microscope.
In known scanning electron microscopes, all observations made on the pieces to be examined are carried out by inserting the pieces into a vacuum chamber disposed at the lower end of an electronic-optical column, and comprising a cup-shaped body of substantially horizontal axis, the inner cavity of which is accessible through a lateral aperture. During observations, this latter is closed in an airtight manner by means of a door, which is normally hinged to a lateral wall of said cup-shaped body so that it rotates relative to this latter about a substantially vertical axis between a closed position and an open position.
Normally a piece holder is connected to said rotatable door,
this piece holder projecting into the cup-shaped body when the door is closed and being arranged to support a piece to be examined in a position which can be adjusted along at least three axes by means of micrometer adjustment devices extending outwards from said door.
In general, the operation involved in mounting a piece for observation on the relative piece holder is extremely long and delicate, as said piece is mounted when the door is open, and must be disposed such that when the door has been closed it is in a position as close as possible to the correct observation position.
This is not always easy to do, and in addition there is always the risk that during adjustment operations made after the door has been closed, the piece strikes against one of the detection devices disposed inside the vacuum chamber. As such a happening must be avoided, known electron microscopes normally comprise a generally acoustic alarm system which warns the operator when the piece to be observed strikes against any obstacle.
In spite of the use of alarm systems, the adjustment of the position of the piece before observations is always problematical and laborious, and requires a time such as to drastically reduce the actual time available for making observations with the microscope.